Do not press on the plunger of the syringe. You’ll soon start receiving the latest Mayo Clinic health information you requested in your inbox. These include itraconazole Sporanox, Tolsura , ketoconazole Extina, Ketozole, others and ritonavir Norvir. Keep out of the reach of children. And not all online pharmacies have the capability to safely ship medications that need to be temperature-controlled, such as insulin. Follow your doctor’s orders or the directions on the label.To find out more about how Viagra is used for ED, see the “What is Viagra used for?” section below. Read on to learn more about how Viagra works, how long it . The four main medicines taken by mouth for erectile dysfunction are: Avanafil (Stendra). Sildenafil (Viagra). Tadalafil (Cialis). Vardenafil. These medicines are called .  · Sildenafil (Oral Route) Sildenafil is used to treat men who have erectile dysfunction (also called sexual impotence). Sildenafil belongs to a group of medicines .